Following changes to the BSI standards on fire extinguishing installations, David Smith reports on the reasons for the revision and what the new requirements mean in practice
28 July 2006
It was in 1932 that the British Standards Institution (BSI) first published a code of practice relating to the provision, installation and maintenance of fire mains within buildings. This document, CP 402.101, was updated at various times until it was eventually replaced by BS 5306-1 in 1976 as part of a major revision by BSI of the series of codes dealing with the provision of particular items of equipment for fire-fighting installations within buildings.
The BS 5306 suite of standards all deal with fire-extinguishing installations and equipment on premises, and although Part 1 was actually titled Hydrant systems, hose reels and foam inlets, the material relating to hydrants also covered risers. Minor amendments, mainly to reflect changes in other codes or regulations, were made to BS 5306-1 in the 1980s since when it has remained unchanged.
As a result of reviews of fire-fighting practices undertaken by the Building Disaster Assessment Group (set up in the UK after 9/11 to consider issues for fire services) a number of research projects were commissioned in 2004 that revealed a need for revision of BS 5306-1.
The research concluded that over time there had been a number of changes to fire service operational procedures and equipment which had not taken account of the original technical basis for the provisions in BS 5306-1. Notably, the use of smaller bore hose - used because it was lighter and easier to manoeuvre - had resulted in reduced capabilities for fire-fighting at the point of delivery of the water. In addition, some of the new delivery nozzles designed to provide a protecting screen for the fire-fighter required pressures at the inlet to the nozzle that were higher than could be provided from a rising main designed in accordance with the current standard. Other issues were also identified and work on revising the standard began in March 2005.
The decision was taken to partially replace BS 5306-1 with a new British standard, BS 9990:2006 which would deal only with fire mains and their associated water delivery equipment. It would no longer give guidance on when and where such systems are needed, which is now given in, for example, guidance in support of national building regulations. The new standard therefore deals only with the design of the systems, including recommendations for their provision, siting, installation and maintenance.
The BSI committee responsible for producing the standard initially believed that guidance on hose reels and foam inlets was already incorporated in other standards and was thus now redundant. During the standards making process, however, it was discovered that although requirements for hose reels and their maintenance was contained in other standards, certain guidance on hose reels and foam system inlets was not covered elsewhere and it has therefore been retained in a revised BS 5306-1:2006.
What the changes mean
One of the key considerations made by the BSI committee in producing the new standards is that fire protection of a building should be considered as a whole. The provision of fire mains is an essential element of fire protection systems in large and complex buildings due to the difficulties in providing water supplies at the point of use for fire-fighting and search and rescue. It is therefore essential that these systems are properly and adequately designed, installed and maintained to ensure instant readiness when required.
The revisions themselves are not retroactive, so there is no need to replace existing vertical fire mains (wet or dry risers) in buildings. This is not to say, however, that modifications to existing provisions will never be needed. The changes came about largely as a result of insights into fire-fighting, particularly in high rise buildings, and while changes are concurrently being made in fire service operational procedures and equipment there may be instances where it is considered advisable to upgrade the vertical mains to enable more effective fire-fighting to be undertaken.
The new BS 9990:2006 will apply to all new installations and also where major refurbishment takes place. No change has been made in the minimum size of vertical mains but larger diameters may be necessary to achieve the new specifications relating to required minimum flows and pressures at outlets.
Whereas the original standard called for a maximum outlet pressure at a landing valve of 7 bar, the new standard requires a minimum of 8 bar and, for wet mains, a maximum of 10 bar. There are also new requirements relating to isolating valves on vertical mains so as to enable lower sections to be operational when maintenance is required at higher levels.
BS 9990:2006 also brings up to date the guidance on private fire mains (both internal and external) and gives recommendations for non-automatic fire-fighting systems in buildings. It covers good practice in matters affecting the design, installation, testing and maintenance of such systems including wet and dry fire-fighting mains.
BS 5306-1:2006 now contains only the residual material which deals with hose reels and foam inlets and this has been updated. It covers good practice in matters affecting the design, installation, testing and maintenance of such systems.
Neither of the new or revised standards cover hose reels, foam inlets, automatic foam systems and portable fire-fighting equipment. These systems are covered in BS EN 671-1, BS 5306-3, BS 5306-8 and BS EN 3-7. Requirements for the hose reels themselves are specified in BS EN 671.
David Smith is chair of FSH/14 the BSI committee for fire precautions in buildings